CODEWITHSUNDEEP
c++
JASON
JASON

Reputation: 7491

what's the best way to get rid of the \0 at the end of a string literal?

I'm trying to do something like

strcmp(argv[3], "stdout")

however, in the command line I don't want to type 

stdout\0

what's the best way to get rid of the \0 at the end of a string literal?

Thanks!

update:

Thanks guys. I found what's wrong with my code... I should have used

strcmp(argv[3], "stdout") == 0

Thanks @Nicol Bolas

Upvotes: 0

Views: 307

Answers (3)

billz
billz

Reputation: 45410

A string literal consists of zero or more characters from the source character set surrounded by double quotation marks ("). A string literal represents a sequence of characters that, taken together, form a null-terminated string.

strcmp starts comparing the first character of each string. If they are equal to each other, it continues with the following pairs until the characters differ or until a terminating null-character is reached.

so you don' t need to write \0 in the end of stdout, you need to compare the return value of strcmp to 0:

if (strcmp(argv[3], "stdout") == 0)

Upvotes: 2

Platinum Azure
Platinum Azure

Reputation: 46193

You don't need to type \0 in most cases. String literals have a \0 implicitly appended to them, and the C functions that store string data into character arrays will append a \0 on the end (which is why the documentation for many of those functions specifies that your character buffer must have enough space for the string and the null terminator).

Upvotes: 2

Adam Mihalcin
Adam Mihalcin

Reputation: 14458

You don't have to type "stdout\0" on the command line. Whichever way your system makes command-line arguments available to your process (it differs by operating system) automatically adds the null character.

As you know, a C-style string is terminated by the null character, which is written in code as '\0'. If that character weren't at the end of the string, a function such as strcmp would keep going well beyond the end of the string, since such a string flouts convention. Since the terminating null character is the C convention, however, the compiler is smart enough to add the null character to the end of a string literal, and the system is smart enough to add the null character to the command-line arguments stored in the memory of a freshly created process. If argc is greater than 3, and the third argument you type on the command-line for your program is "stdout", the call to strcmp(argv[3], "stdout") will return 0 to mean that the two strings match.

Upvotes: 3

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